Research Of Group Phase Quantization Processing And The Key Technologies Based On Different Frequencies Signals

The improvement of precision and the simplification of device are the direction of development in measurement, comparison, control, PLL circuit, frequency conversion and synthesis, phase noise measurement and signal processing of atomic frequency standard of time-frequency signal. Because measurement, comparison, and control of the time-frequency signal are built on the basis of mutual relations, it is necessary to obtain high-precision contents of characteristics from the beginning of mutual relationships between frequency signals. The traditional high-precision signal processing method is based on continuous phase (or frequency) comparison processing and the normalized frequency, namely the frequency nominal value must be same or be strict with frequency relations in usual phase comparison and processing. In some cases, the complex frequency conversion is to be introduced in order to compare in wide frequency range or between the signals of specific different nominal value, which the high-precision phase comparison and wide application are greatly limited. In recent years, development of foreign technology in this area, on the one hand is improved from the line circuit by microelectronic technology, on the other hand is optimized from the algorithms by micro-processing technology. However, the phase processing method is usually used in traditional time-frequency signal processing technology. Here, these algorithms and processing methods that can compare must be based on the same frequency signals. The different frequency signal can be processed only by the method of frequency conversion. Therefore, if phase comparison is completed in wide frequency measurement range, it is necessary to use high-precision frequency synthesizer. In this cases, measurement equipment is not only complex, but also is easy to introduce additional error of synthesizer, which is inevitable in the traditional phase approach. In this paper, these defects can be fundamentally changed and effectively resolved in support of a series of new concepts and theories of different frequency signals. These new concepts and theories, including phase quantum, group Phase quantum, difference group phase, group phase difference, group shift, group period, group synchronization, group period phase comparison and group phase control and so on, are based on the important parameters which characterize relationships between frequency signals, such as the greatest common factor frequency, the least common multiple period, quantized phase shift resolution, equivalent phase comp(?) frequency and so on. Therefore, the method based on group phase quanti processing between different signals is more suitable for high-precision frequency signal processing. The key technologies of method may affect the development of time-frequency measurement and control technology. Therefore, the measurement, comparison and control based on the same frequency are extended to any frequency signal by the related concepts and the corresponding signal processing scheme based on group phase quantization. The main contribution in this field includes the following:1. According to the basic phase relations between different frequency signals, the concept of group phase quantum is proposed, and the basic law of group phase difference, the characteristics of group phase quantum, and±1 counter error eliminated based on group phase coincidences are deeply analyzed. Using these concepts and characteristics in time and frequency signals processing, combining group phase coincidences and its detection principle, high measurement resolution can be easily reached.2. A group period phase comparison method is proposed based on the concept of group phase quantum. The method reveals the variation law of group phase difference and the inherent relations between periodic signals. Using these laws in frequency signals processing, linearity phase comparison can be completed without the same frequency between them. Experimental results show the method is scientific and advanced. Resolution of Comparison and measurement and control based on group phase quantum can reach 10-12/s level.3. On the basis of group period phase comparison technology, a high-precision frequency measurement method is proposed based on different frequency phase processing. Using the variation law of group phase quantum and the distribution law of group phase coincidences between different frequency signals,±1 counter error existing in traditional frequency measurement is eliminated by establishing measuring gate between two group phase coincidences. The pulse numbers of the phase coincidences clusters can be decreased by pulse width adjustable circuit and the optimal phase coincidences can be seized easily by phase coincidence control circuits, which will reduce the randomness of the count strobe action, and measurement precision of system will be greatly improved. In order to ensure the measurement of arbitrary signals, a new frequency measuring scheme which has self-adaptive ability is proposed. a frequency standard signal which has a certain frequency relations with measured signal is automatically synthesized by introducing DDS and the value of measured signal as a reference, which ensure the controllability of phase relations between measured signal and frequency standard signal, and finally realize high-precision measurement of arbitrary frequency signal. Based on this, if we improve the stability of DDS output signal, reduce the noise of system, improve the accuracy capturing group phase coincidences, and further improve the existing question in group phase quantum processing, super-high resolution over ps level can be obtained. Experimental results show measuring resolution can reach 10-13/s in time domain. Compared to conventional frequency measurement system, the new scheme is high in measurement precision, simple in circuit structure, low in cost and high in system stability.4. According to the mutual relations between frequency signals and the variation law of group phase difference, a novel phase noise measurement system is proposed based on different phase processing. Phase difference information is achieved by different frequency phase comparator. After the information is processed by LPF and related signal circuits, voltage control signal of reference source can be obtained. Phase lock can be realized, and then phase noise information of measured signals can be extracted. Then the phase noise information is sent to spectrum analyzer, thus high precision measurement of phase noise is realized. The system may complete phase noise measurement between any frequency signals using a high precision reference source of low phase noise in a wide voltage control range. Using different frequency phase processing in phase noise measurement system is new breakthrough in phase noise measurement domain. The improvement of measurement precision does not only depend on the improvement on circuit, but using the inherent relations and variation law between periodic signals, these relations and laws are used in phase noise measurement. As further research of phase noise measurement system, a novel seamless digital phase noise measurement scheme is proposed based on group phase quantum. The phase coincidences ar detected between reference signal by double frequency and simple frequency synthesis and measured signal frequency. According to seamless counter between phase coincidences, variation of phase noise is reflected by the variation of counter value or phase fluctuation in two continuous phase coincidences. SSB is calculated by DFT and computer data processing. Digital high precision phase noise measurement is finally realized.5. According to the stability of electromagnetic wave transmission in space or special medium, a high-resolution time interval measurement method is proposed based on time-space conversion. Measured time interval is quantized in this m(?) Combined phase coincidence detection technology, measurement of time is convei measurement of space length. Using the principle of time and space conversion in precise time interval measurement is new breakthrough in time interval measurement domain. The improvement of measurement precision does not only depend on the improvement on circuit, but the fact that electromagnetic signal only delays time, but doesn't generate variation in shape. Compared to traditional time interval measurement method, it is a complete different way in measurement principle.6. Although Time interval measurement method based on time-space relationships has a high measurement resolution, its measuring range is very sorrow. In order to further widen its measuring range, a new short time interval measurement method is proposed based on delay-time multiplexing technique. Using the time interval measurement principle based on time-space relationship, a delay chain will be composed of several delay-time units. Output of the delay chain is fed back to system input end and judged by mono-stability trigger logic with original input signal. The result of the judgment is sent back to the coincidence detection circuit, which realizes cycle detection that a delay chain can be repeatedly used. Thus time interval measurement range based on time-space relationship is expanded, and the stability of measurement system is improved. The results of experiment and analysis show that the method is scientific and advanced, and its measurement resolution from ten ps level to ps level can be reached.7. A new time-frequency measurement method is proposed based on length vernier. Using length vernier method to measure time interval is a new technique. A lot of experiments prove the fact that high-resolution time interval measurement is easily achieved by time-space relations. The device using the measurement method can reach measurement resolution of ten ps level. The method used in time synchronization technology ensures strict time synchronization and high-stability output, which greatly improve whole performance of device.8. A novel design scheme of phase-locked system of hydrogen maser frequency standard is proposed based on equivalent phase comparison frequency. Using the regularity of the variation of phase difference between frequency signals, linear phase comparison is possible without the same frequency between them, namely different frequency phase comparison. If different frequency phase comparison is used in PLL of the hydrogen maser frequency standard, through suitable choice of the equivalent phase comparison between reference signal and locked signal, we can directly compared phase between different frequency signals and obtain very high phase-locked precision. Experimental results show that the design scheme is advanced and scientific. Its phase-locked precision can reach the order of magnitude of 10-12/s. Compared to traditional phase-locked system of hydrogen maser frequency standard, the system is high in phase-locked precision, simple in circuit structure, small in additional noise, and can be direct phase comparison between different frequency signals. Thus it is widely used in navigation positioning, space technology, communication, precise time-frequency measurement and control and so on.9. A new design scheme for second-class frequency standard locked system based on GPS is proposed. Using the delay stability of signal and the regular changes of group phase difference, a high-precision time interval measurement method is generated based on length vernier. If the method is used in the second-class frequency standard locked system, by multi-scale Kalman filter of measured time interval, the relative frequency difference between GPS and divided frequency signal of second-class frequency standard can be calculated under the control of MCU. According to frequency-voltage control characteristics of second-class frequency standard, a compensation voltage can be obtained. After the compensation voltage is converted by D/A, it is sent to voltage control end. Then output frequency of the second-class frequency standard can be adjusted. Thus second-class frequency standard locked system is formed. Experimental results show that the system locked precision is as high as 10-12/s in time domain. Compared to traditional frequency standard locked system, the system has the advantages of simple structure and low cost and small additional noise and high locked precision.